The overall objective of this integrated group of research studies is a more comprehensive understanding of the pathophysiology of manic-depressive disorders, particularly with regard to the complex interrelationships among clinical phenomenology, diagnosis, biological variables, and pharmacologic response. The studies are longitudinal; drug trials are double-blind. Major foci during the past year include: (1) the study of regularly cycling manic-depressive patients, and the use of drugs to modify cycle length and intensity; (s) the evaluation of tricyclic antidepressants showing relative specificity for a given amine neurotransmitter; (3) the pharmacokinetics of tricyclics; (4) the evaluation of experimental drugs such as pimozide, cyproheptadine, piribedil and L-tryptophan; (5) the use of psychological testing and auditory evoked response to predict drug response. BIBLIOGRAPHIC REFERENCES: Carmen, J., Post, R.M., Goodwin, F.K. and Bunney, W.E., Jr.: Calcium and Electroconvulsive Therapy of Severe Depressive Illness. Biol. Psychiat. 12:5-7, 1977. Goodwin, F.K.: Diagnosis of Affective Disorders. In Jarvik, M. (Ed.): Psychopharmacology in the Practice of Medicine. New York, Appleton-Century-Crofts, 1977, pp. 219-228.